Nonmicrophonic support for vacuum tubes



May 24, 1932. c. A. GUNTHER NONMICROPHONliC SUPPORT FOR VACUUI TUBES.Filed Aug. 31, I928 Inventor- Clarence AGunther,

kzy His Attornqg I stems with small damping fac'tors. sy electrode orparts thereof varies the out 15 that shocks or vibrations g ally is thistrue when several are connected in tandem, when each tube in j may a onean conducting of the radio frequency circuits connected with '43 showsline 33 of 1. Numeral 1 indicates a bers plurality of evacuatedenvelopes containing various electrodes Patented Ms DsTATrs PATENTOFFICE.

crimson a. comma, or many, new vonx, sssrenon r0 GENERAL amorarc comm, aooaroaarrox or mew YORK nomcnornoivrc surronr ron VACUUI mas Applicationfiled'Auguet $1.1m. Serial in. 803,818.

- "The present invention .relates to electric "discharge a paratus andmore particularly to non-micro honic supports for thermionic deviceswhic .are mounted upon vehicles or in other places where they aresubject to shocks,

jam or' vibrations. It has been found 'thattheelectrodes of vacuumtubes, as they are usually construct-4 ed, almost always tend to act as'vibragy 3 relative movement of the ut or space current which passes ina circuit including the cathode and anode of such tubes, and hence, itis seen impressed uponthe tube so astocalise'the. electrodes to vibratein their several respective periods will cause troublesome noises in atelephone bridged across the output circuit of the tube. Especiamplifiertubes addition to amplifying the current variations of th'e'precedintube will add a series of variations due toe vibrations of its ownelements; The trouble due to vibrations of the electrodes is not limitedto tubes incas: cade but is usually present where vacuum tubes aremounted on a solid structure subject to vibrations, such as-aeroplane,boat or 30 other moving vehicle. Moreover, it has been do the elementswithin each tube move so as to change the interelectrode spacing, but.the tubes themselves change their position with respect to er and alsowith respect to adjacent surfaces which causes detuning found that notonly the various electrodes.

'An fleet of this invention is to produce a 4a practi structure toovercome the difliculties mentioned. In the; Fig.1 represents anelevational view partly in crosssection of the improved tube assemblsupport;-'Fig. 2-is. a' pla n'view, while ig. 3

in c w: v. the, view taken along which may constitute amplifiers,detectors, oscillators or the-like in resilient members 4 tend to rollslig ,ner, substantially uniform flexibility being mounted in theordinary form of.

socket 2, which'may be secured in suitable manner to a base-board 3 ofinsulating material, for example, fiber. The base-board rests upon aplurality of hollow members or cushions 4 which may be constituted of himy elastic. material, for example, live ru r, the cushion members beingsupported on a lower base-board-5 also preferably of fiber. While thesemembers may take various shapes, for example, hollow spheres, I preferto fashion them as hollow cylinders,

the manufacture of which is facilitated by forming a rubber tubing ofthe desired diameter and cutting ofl. pieces of the requisite length..In some cases, rubber bands having a width of material comparable tothe length of the cylinder may be wound, layer upon layer, until theproper thickness has been reached and securing the ends to form aunitary ring. The dimensions of the cushions are obviously dependentupon many factors including the weig'lht to be supported andcharacteristics of e vibrations to be damped; I have obtainedsatisfactory results by employing live rubber tubing outside diameter,approximatel thick and long for suporting r '0 receiving setsconstituting three to five tubes. 'The pieces of tubing lie lengthwiseand may be aflixed' to the base-boards in any suitable manner, forexample, by diametrically disposed rivets which pass through the boards.It is obvious in the event that shock, jar or vibration is transmittedto the tube assembly, as

- when the set is an accessory toan automobile,

aeroplane, boat or other moving bod th h being held-in place by therivets,.they simply distort, and the to mount the tubing so that thelongitudinal axes of adjacent memare normal to each otherpin thismandlrections. of the transverse plane may be obtained, although, it'n-zto be understood that resulting strain; dissi 'pates or otherwise thevibrational energy from the assembly. considered preferable for the moreeflicacious removal of the shock energy,

min

3 e y but any and all relative poaitionsof flie van'om members 4 arewithin the contemplation of my invention. In the event that the shock issevere, as when an aeroplane equipped with the device hereinbeforedescribed is landing on rough terrain, the tubing members may flatten toa considerable extent and it may be desirable to provide a bumper 6,constituted of sponge rubber, to serve as a stop or limit to therelative movement between the baseboards. The thickness of the spongerubber block should be such as to permit the tubing to distort orflatten to a degree just sufficient for dissipating the shock energy.

Moreover, it has been found that when the receiver is connected to radiofrequency circuits, the swinging of the respective tubes about theirsockets may cause a slight but readily perceptible detuning of thevarious circuits. These movements apparently produce a change in therelative positions of each group of electrodes considered as a wholewith respect to one another and with respect to adjacent conductingsurfaces thereby varying the constants of the associated circuits. Inorder to prevent these gyrations, 1 provide a quantity of sponge rubber7, conveniently in block or plate form, fashioned to fit snugly aboutthe envelope of each thermionic device by means of appropriately shapedapertures; this plate member serves to space the tubes from one anotherand from nearby conductors. The block may acquire rigidity from ametallic plate 8 preferably of non-magnetic material, for example,aluminum, the combined structure being supported from the lowerbase-board by means of two sets of oppositely positioned brackets 9, 9which pass through suitably located notches in the upper base-board 3and the bumper 6. The brackets may be aflixed to the sponge rubberstructure by rivets 10, 10 and to the lower base-board by screws or inany other manner. While it is evident that various forms of leading-inconductors, 11 may be employed to make connection with the tubecontacts, I prefer to utilize flexible metallic braid for this purpose,so as to prevent extraneous vibrations from being communicated to theelectrodes which ordinarily would happen if the leads were made of solidmetal.

, t will be apparent that in providing elastic means for damping out themechanical vibrations derived from any extraneous source which otherwisemay be transmitted to the electrodes of the tubes and further, inproviding a resilent spacer between the tubes to prevent detuning of thevarious circuits, the construction is admirably adapted for supportingaudion tubes and produces the maximum degree'of quietness in the outputof such tubes under diflicult operating conditiuns. The live rubbertubing tends to dispose of at least two forms of acoustic undulations,the sharp, relatively small amplitude,intermittent jar or vibrationbeing effecsponge rubber which is employed for members 6 and 7 serves toeliminate or reduce the effect of heavy thrusts exerted by the upperbase-board in moving toward the lower board or by the swinging motion ofthe various tubes; the air cells of the sponge rubber constitute amultitude of dash pots in draining the vibrational energy from thevarious parts of the apparatus producing a high damping factor.

It is evident that other caoutchouc-like materials may be substitutedfor each of the live rubber and sponge rubber having similar resiliencyand damping properties. No attempt has been made herein to enumerate ordescribe all the possible damping materials or means and otherequivalent structure and devices which may be used in carrying on thepurposes of the invention but the appended claims are intended toinclude such equivalents except where otherwise specified.

For example, in place of hollow cylinders, an-

nular members of damping material in the form of helices may be used.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

' 1. A support for preventing external vibrations from changing thespace relations of electrodes in space current apparatus, said support"comprising a plurality of cylindrically shaped members of elasticmaterial having longitudinal axes angularly disposed with respect to oneanother, said apparatus resting upon said members, whereby thevibrational energy is dissipated in a plurality of directions.

2. A mounting arrangement for space discharge apparatus, comprising abase-board upon which the apparatus is mounted, a subbase-board, anonmicrophonic member interposed between said base-boards, said membercomprising tubing of caoutchouc material which lies lengthwise of thebase-boards.

3. A mounting for space discharge apparatus which normally is subject tovibrations, said mounting comprising a base-board upon which theapparatus is mounted, a sub-baseboard and means interposedbetween thebase.-

within each tube and the constants of the associated circuits arealtered, means for maintaining the normal electrode spacing, said meanscomprising a plurality of hollow cylindrical e1ast1c members upon theperiphery of which the apparatus is supported and a spacer of resilientmaterial positioned between the tubes. V p I 5. A support for a radiofrequency amplifier, said amplifier comprising a plurality of trodespacing within eac ermionic. devices which tend normally to vibrate dueto extraneous mechanical disturbances thereby chan 'ng theinter-elecdevice also chang ing the spacing between the electrodes ofsuch devices and adjacent conducting surfaces whereby deleteriouseffects are produced in the output of the amplifier, means formaintaining the normal electrode spacing, said means comprising hollowcylindrical members of elastic material upon the periphery 'of whlch theamplifier is supported, said members being subject to distortion ofshape when activated by said disturbances, a block of resilient materialto limit the amount of said distortion and a spacer of energy-dampingsubstance positioned between said devices.

In witness whereof I have hereunto set my hand this th da 0 August,1928.

GLAR NCE A. GUNTHER.

